Weeks before Vikram S. Pandit’s surprise resignation on Tuesday as chief executive of Citigroup, the banking giant’s powerful chairman, Michael E. O’Neill, was privately huddling with other board members to plan how to replace him, according to several people briefed on the talks.

That didn't take long. The economy hasn't yet recovered from the implosion of risky investments that led to the worst recession in decades—and already some of the world's biggest banks are peddling a new generation of dicey products to corporations, consumers, and investors.

The Federal Deposit Insurance Corp. isn't the only beneficiary of a plan to refill its coffers. The proposal, which the banking regulator announced on Sept. 29, also offers an intriguing way for financial firms to boost their capital and raise their profits.

Some of America's biggest banks -- including Bank of America Corp., J.P. Morgan Chase & Co., and Bank One Corp. -- hold billions of dollars in so-called janitors insurance on their present and former employees. But investors may have a hard time finding much information in their Securities and Exchange Commission filings.